Background: The etiology of bone disease in thalassemic patients is multifactorial. Factors such as hormonal deficiency (especially gonadal failure), bone marrow expansion, increased iron stores, desferioxamine toxicity, calcium, and vitamin D deficiency seem to have a serious impact on impaired bone metabolism in this disease.
Objectives: To estimate the frequency of calcium homeostasis abnormalities in adolescent thalassemic patients, and to investigate the effect of a megadose of vitamin D3 on these parameters.
Methods: Thirty fully pubertal adolescent thalassemic patients aged 1535 years completed an experimental trial for 1 year where they received an i.m. dose (600 000 IU) of cholecalciferol at the beginning of the study. Parameters of calcium homeostasis (serum calcium, phosphorus, alkaline phosphatase (ALP), parathyroid hormone (PTH), and 25 hydroxyvitamin D (25OHD)) were measured at 0, 6, and 12 months. Vitamin D insufficiency was defined when 25OHD ranged from 20 to 30 ng/ml and deficiency when 25OHD level was <20 ng/ml.
Results: At baseline, ten patients (33.3%) were hypocalcemic, 23 (76.6%) were hyperphosphatemic, 12 (40%) had high serum ALP, 4 (13.3%) had 25OHD deficiency and 13 (43.3%) had 25OHD insufficiency. At 6 months, one patient (3.3%) was vitamin D deficient and three patients (10%) were insufficient. At 12 months, two patients (6.6%) were deficient and five patients (16.6%) were insufficient. There was a significant effect of vitamin D injection on serum calcium level at 12 months (P=0.036), serum ALP level both at 6 (P=0.009) and 12 months (P=0.006), and on serum 25OHD level both at 6 and 12 months (P=0.000) with no significant effect on PTH level.
Conclusion: A once yearly i.m. cholecalciferol injection (600 000 IU) is a suitable therapeutic option for treating vitamin D deficiency in most patients with β-thalassemia major.
20 - 22 Sep 2014
European Society for Paediatric Endocrinology